Combined approach of high-power and very high-power, short-duration ablation in superior vena cava isolation.

INTRODUCTION: The effectiveness and safety of 50 W, high-power, short-duration (HPSD) ablation in superior vena cava isolation (SVCI) for patients with atrial fibrillation (AF) have been reported. However, the acute outcomes of SVCI combined with 90 W/4 s, very high-power, short-duration (vHPSD) ablation remain unknown. In this study, we aimed to investigate a novel approach that combines 50 W-HPSD and 90 W/4 s-vHPSD ablation in SVCI and to elucidate the characteristics, outcomes, and safety of this approach by comparing SVCI with conventional ablation index (AI)-guided middle-power, middle-duration (MPMD) ablation. METHODS: Overall, 126 patients who underwent AF ablation with SVCI using the QDOT MICROTM catheter were retrospectively reviewed; one group underwent SVCI with a combined approach of HPSD and vHPSD ablation (50 W/90 W group, n = 73) and another group underwent AI-guided MPMD ablation (30-40 W group, n = 53). This study compared the procedural details, radiofrequency (RF) ablation profiles, and complications. The RF settings used in the 50 W/90 W group were 50 W/7 s for the lateral segment close to the phrenic nerve and 90 W/4 s for the nonlateral segment. RESULTS: The 50 W/90 W group required a significantly shorter procedural time (3.2 vs. 5.9 min, p < .001), shorter RF duration (42.0 vs. 162.0 s, p < .001), and lower RF energy (2834 vs. 5480 J, p < .001) than the 30-40 W group. Procedural success, first-pass SVCI, number of RF applications, and SVC reconnection after isoproterenol loading were comparable between the groups. The maximum tip-electrode temperature of the multi-thermocouple system was significantly higher in the 50 W/90 W group than in the 30-40 W group (50.0°C vs. 47.0°C, p < .001). No complications, such as phrenic nerve injury or bleeding requiring transfusion, were observed in either group. CONCLUSIONS: The combined approach of 50 W/7 s-HPSD and 90 W/4 s-vHPSD ablation resulted in successful and safe SVCI with shorter procedural time, shorter RF duration, and lower RF energy.

Dual linear lesions for right atrial flutter after mitral valve surgery via the superior transseptal approach.

BACKGROUND: The superior transseptal approach (STA) for mitral valve surgery is associated with a higher risk of developing macroreentrant incisional atrial flutter (AFL) than the left atrial approach. This study aimed to describe the linear lesions for the complex AFL circuit after the STA and to propose an option for the linear ablation target site. METHODS: Of the 26 patients who underwent radiofrequency catheter ablation for AFL after mitral valve surgery, data from seven patients with STA incisions were retrospectively analyzed. RESULTS: All patients who had undergone the STA had incisional AFL rotated in a long loop within the right atrium (RA) and cavo-tricuspid isthmus (CTI)-dependent AFL. The linear lesions were created in the CTI, the superior RA vestibule, and between the RA-free wall incision or the septal incision and the inferior vena cava. Procedural success was achieved with dual linear lesions in the CTI and superior RA vestibule. Two of seven patients had AFL recurrence during a mean observation period of 22.5 ± 16.7 months. The circuits of recurrent AFL were CTI-dependent AFL and perimitral AFL, respectively. No AFL recurrence was noted with reconduction of the superior RA vestibular lesion. CONCLUSION: Dual linear lesions in the CTI and superior RA vestibule are an effective treatment option for RA macroreentrant AFL after the STA.

Clinical anatomy of the right intercostal arteries: Another neighbor to know before pulmonary vein isolation.

BACKGROUND: Hemothorax caused by a right intercostal artery (ICA) injury behind the left atrium (LA) is a potentially fatal complication during pulmonary vein isolation. However, their anatomical relationship has not been fully elucidated. OBJECTIVE: This study aimed to investigate the clinical anatomy of the right ICA in relation to the LA. METHODS: This retrospective study included 100 patients (70.2 ± 10.6 years, 39.0% female) who underwent cardiac computed tomography. The patients were divided into sinus rhythm (SR) and atrial fibrillation (AF) groups. We focused on the distance between the LA and right ICAs and its predictive factors. RESULTS: On average, 3.7 ± 0.7 right ICAs were found behind the LA. Among these, the eighth ICA was the closest in 54% of the cases, followed by the seventh ICA in 29%, and the ninth ICA in 14%. The average closest distance between them was 3.8 ± 3.8 mm, which was significantly shorter in the AF group than in the SR group (3.0 ± 3.2 mm vs. 4.7 ± 4.2 mm, p = 0.006). Multivariate analysis revealed that a thinner chest cavity (ß = -0.512, p = 0.002) and LA dilatation (ß = -0.432, p = 0.001) were predictors of shorter distance. The closest points distributed along the vertebral column, generally near the inferior pulmonary vein orifices. CONCLUSIONS: Right ICA-LA proximity was systematically clarified. Particularly in cases with an enlarged LA and/or thin chest cavity, operators should be aware of the potential risk of injuring the right ICA during pulmonary vein isolation.

MLL2 and KDM6A mutations in patients with Kabuki syndrome.

Kabuki syndrome is a congenital anomaly syndrome characterized by developmental delay, intellectual disability, specific facial features including long palpebral fissures and ectropion of the lateral third of the lower eyelids, prominent digit pads, and skeletal and visceral abnormalities. Mutations in MLL2 and KDM6A cause Kabuki syndrome. We screened 81 individuals with Kabuki syndrome for mutations in these genes by conventional methods (n = 58) and/or targeted resequencing (n = 45) or whole exome sequencing (n = 5). We identified a mutation in MLL2 or KDM6A in 50 (61.7%) and 5 (6.2%) cases, respectively. Thirty-five MLL2 mutations and two KDM6A mutations were novel. Non-protein truncating-type MLL2 mutations were mainly located around functional domains, while truncating-type mutations were scattered through the entire coding region. The facial features of patients in the MLL2 truncating-type mutation group were typical based on those of the 10 originally reported patients with Kabuki syndrome; those of the other groups were less typical. High arched eyebrows, short fifth finger, and hypotonia in infancy were more frequent in the MLL2 mutation group than in the KDM6A mutation group. Short stature and postnatal growth retardation were observed in all individuals with KDM6A mutations, but in only half of the group with MLL2 mutations.

A novel approach to typical atrioventricular nodal reentrant tachycardia with high-resolution mapping using the CARTO 3 cardiac mapping system.

BACKGROUND: We hypothesized that high-resolution activation mapping during sinus rhythm (SR) in Koch's triangle (KT) can be used to describe the most delayed atrial potential around the atrioventricular node and evaluated whether ablation targeting of this potential is safe and effective for the treatment of patients with typical atrioventricular nodal reentrant tachycardia (AVNRT). METHODS: We conducted a prospective, non-randomized, observational study using high-resolution activation mapping from the sinus node to KT with a PENTARAY or OCTARAY catheter using the CARTO 3 cardiac mapping system (Biosense Webster) during SR in 62 consecutive patients (22 men; age [mean ± standard deviation] = 55 ± 14 years) treated for typical AVNRT at our institution from August 2021 to March 2023. RESULTS: In all cases, the most delayed atrial potential was observed near the His potential within KT. Ablation targeting of this potential helped successfully treat each case of AVNRT, with a junctional rhythm observed at the ablation site. Initial ablation was deemed successful in 55/62 patients (89%); in the remaining seven patients, lesion expansion resolved AVNRT. One procedural complication occurred, namely, a transient atrioventricular block lasting 45 s. One patient experienced a transient tachycardic episode by the 1-month follow-up, but no further episodes were noted up to the 1-year follow-up. CONCLUSION: Activation mapping at KT during SR with the high-resolution CARTO system clearly revealed the most delayed atrial potential near the His potential within KT. Targeting this potential was a safe and effective treatment method for patients with typical AVNRT in our study.

Successful penetration and bougie dilatation with Brockenbrough needle for severely calcified occlusion in superficial femoral artery.

A 75-year-old hemodialysis patient with right critical limb ischemia received endovascular therapy for a chronic total occlusion (CTO) in a diffusely calcified superficial femoral artery (SFA). During a retrograde approach, a Brockenbrough needle (BN) was able to penetrate the calcified hard plaque formed in the middle segment of the CTO. Moreover, bougie dilatation with the BN allowed balloon crossing and stent deployment, even after failure to pass a 2.0-mm monorail balloon across the plaque. These results suggest that the BN offers a new therapeutic option in the penetration and modification of severely calcified CTO in SFA.